Development of Palladium-catalyzed cross-coupling reactions of aryl halides with organosodium and potassium compounds

S-嵌段金属有机化合物，如有机锂或格氏试剂，是合成化学中最重要的有机金属化合物之一，通常用作去质子化和金属化反应的强碱。相比之下，它们在过渡金属催化的C-C偶联反应中的应用较少。对于活性较强(较重)的碱金属有机基尤其如此，它们往往会发生不希望发生的铁屑反应，从而减少甚至防止产物的形成。本研究项目的目标是发展钯催化下的极性金属有机化合物与芳基卤化物的直接偶联反应。因此，无需额外的跨金属步骤即可实现C-C键的形成，从而节省了昂贵且有毒的跨金属试剂和盐废料的产生。直到今天，对于目前已有的催化剂，较重的碱金属有机基的这种转化是非常有限的，或者根本不可行。因此，这一局限性将通过开发基于叶立德取代膦的新型催化剂来解决。由于它们的分子设计，这些配体特别富含电子，因此应该非常适合于掌握这些转化。主要焦点将集中在钾和钠有机基上，它们很少被用于偶联化学，但提供了新的或尚未应用的亲核剂的用途。所制定的议定书将特别针对芳基氯化物的使用，因为它们的成本较低，而且储量更大。总体而言，该项目将在高活性极性金属有机化合物的偶联方面设定新的标准，从而缩小偶联和S-嵌段金属化学方面的差距。

S-Block metal organyls such as organolithium or Grignard reagents are amongst the most important organometallic compounds in synthetic chemistry and are routinely employed as strong bases in deprotonation and metallation reactions. In contrast, their application in transition metal catalyzed C-C coupling reactions is less developed. This is particularly true for the more reactive (heavier) alkalimetal organyls, which more often undergo undesired sidereactions, thus reducing or even preventing product formation. Goal of the research project is the development of the direct coupling of polar organometallic compounds with aryl halides by means of palladium catalysis. Thereby, the C-C bond formation shall be realized without additional transmetallation step, thus saving expensive and toxic transmetallation reagents and the generation of salt waste. Until today, such transformations of the heavier alkali metal organyls are very limited or not feasible at all with so far existing catalysts. Thus, this limitation will be addressed by development of new catalysts based on ylide-substituted phosphines. Due to their molecular design these ligands are especially electron-rich and thus should be perfectly suited to master these transformations. Main focus will be set on potassium and sodium organyls, which have hardly been employed in coupling chemistry but offer the use of new or not yet applied nucleophiles. The developed protocol will particularly target the use of aryl chlorides due to their lower costs and broader abundance. Overall, this project will set new standards in the coupling of highly reactive polar organometallic compounds and hence close a gap in coupling and s-block metal chemistry.